/* Open Asset Import Library (assimp) ---------------------------------------------------------------------- Copyright (c) 2006-2024, assimp team All rights reserved. Redistribution and use of this software in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the assimp team, nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission of the assimp team. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ---------------------------------------------------------------------- */ /** @file SkeletonMeshBuilder.cpp * @brief Implementation of a little class to construct a dummy mesh for a skeleton */ #include #include using namespace Assimp; // ------------------------------------------------------------------------------------------------ // The constructor processes the given scene and adds a mesh there. SkeletonMeshBuilder::SkeletonMeshBuilder(aiScene *pScene, aiNode *root, bool bKnobsOnly) { // nothing to do if there's mesh data already present at the scene if (pScene->mNumMeshes > 0 || pScene->mRootNode == nullptr) { return; } if (!root) { root = pScene->mRootNode; } mKnobsOnly = bKnobsOnly; // build some faces around each node CreateGeometry(root); // create a mesh to hold all the generated faces pScene->mNumMeshes = 1; pScene->mMeshes = new aiMesh *[1]; pScene->mMeshes[0] = CreateMesh(); // and install it at the root node root->mNumMeshes = 1; root->mMeshes = new unsigned int[1]; root->mMeshes[0] = 0; // create a dummy material for the mesh if (pScene->mNumMaterials == 0) { pScene->mNumMaterials = 1; pScene->mMaterials = new aiMaterial *[1]; pScene->mMaterials[0] = CreateMaterial(); } } // ------------------------------------------------------------------------------------------------ // Recursively builds a simple mesh representation for the given node void SkeletonMeshBuilder::CreateGeometry(const aiNode *pNode) { // add a joint entry for the node. const unsigned int vertexStartIndex = static_cast(mVertices.size()); // now build the geometry. if (pNode->mNumChildren > 0 && !mKnobsOnly) { // If the node has children, we build little pointers to each of them for (unsigned int a = 0; a < pNode->mNumChildren; a++) { // find a suitable coordinate system const aiMatrix4x4 &childTransform = pNode->mChildren[a]->mTransformation; aiVector3D childpos(childTransform.a4, childTransform.b4, childTransform.c4); ai_real distanceToChild = childpos.Length(); if (distanceToChild < ai_epsilon) { continue; } aiVector3D up = aiVector3D(childpos).Normalize(); aiVector3D orth(1.0, 0.0, 0.0); if (std::fabs(orth * up) > 0.99) { orth.Set(0.0, 1.0, 0.0); } aiVector3D front = (up ^ orth).Normalize(); aiVector3D side = (front ^ up).Normalize(); unsigned int localVertexStart = static_cast(mVertices.size()); mVertices.push_back(-front * distanceToChild * (ai_real)0.1); mVertices.push_back(childpos); mVertices.push_back(-side * distanceToChild * (ai_real)0.1); mVertices.push_back(-side * distanceToChild * (ai_real)0.1); mVertices.push_back(childpos); mVertices.push_back(front * distanceToChild * (ai_real)0.1); mVertices.push_back(front * distanceToChild * (ai_real)0.1); mVertices.push_back(childpos); mVertices.push_back(side * distanceToChild * (ai_real)0.1); mVertices.push_back(side * distanceToChild * (ai_real)0.1); mVertices.push_back(childpos); mVertices.push_back(-front * distanceToChild * (ai_real)0.1); mFaces.emplace_back(localVertexStart + 0, localVertexStart + 1, localVertexStart + 2); mFaces.emplace_back(localVertexStart + 3, localVertexStart + 4, localVertexStart + 5); mFaces.emplace_back(localVertexStart + 6, localVertexStart + 7, localVertexStart + 8); mFaces.emplace_back(localVertexStart + 9, localVertexStart + 10, localVertexStart + 11); } } else { // if the node has no children, it's an end node. Put a little knob there instead aiVector3D ownpos(pNode->mTransformation.a4, pNode->mTransformation.b4, pNode->mTransformation.c4); ai_real sizeEstimate = ownpos.Length() * ai_real(0.18); const ai_real zero(0.0); mVertices.emplace_back(-sizeEstimate, zero, zero); mVertices.emplace_back(zero, sizeEstimate, zero); mVertices.emplace_back(zero, zero, -sizeEstimate); mVertices.emplace_back(zero, sizeEstimate, zero); mVertices.emplace_back(sizeEstimate, zero, zero); mVertices.emplace_back(zero, zero, -sizeEstimate); mVertices.emplace_back(sizeEstimate, zero, zero); mVertices.emplace_back(zero, -sizeEstimate, zero); mVertices.emplace_back(zero, zero, -sizeEstimate); mVertices.emplace_back(zero, -sizeEstimate, zero); mVertices.emplace_back(-sizeEstimate, zero, zero); mVertices.emplace_back(zero, zero, -sizeEstimate); mVertices.emplace_back(-sizeEstimate, zero, zero); mVertices.emplace_back(zero, zero, sizeEstimate); mVertices.emplace_back(zero, sizeEstimate, zero); mVertices.emplace_back(zero, sizeEstimate, zero); mVertices.emplace_back(zero, zero, sizeEstimate); mVertices.emplace_back(sizeEstimate, zero, zero); mVertices.emplace_back(sizeEstimate, zero, zero); mVertices.emplace_back(zero, zero, sizeEstimate); mVertices.emplace_back(zero, -sizeEstimate, zero); mVertices.emplace_back(zero, -sizeEstimate, zero); mVertices.emplace_back(zero, zero, sizeEstimate); mVertices.emplace_back(-sizeEstimate, zero, zero); mFaces.emplace_back(vertexStartIndex + 0, vertexStartIndex + 1, vertexStartIndex + 2); mFaces.emplace_back(vertexStartIndex + 3, vertexStartIndex + 4, vertexStartIndex + 5); mFaces.emplace_back(vertexStartIndex + 6, vertexStartIndex + 7, vertexStartIndex + 8); mFaces.emplace_back(vertexStartIndex + 9, vertexStartIndex + 10, vertexStartIndex + 11); mFaces.emplace_back(vertexStartIndex + 12, vertexStartIndex + 13, vertexStartIndex + 14); mFaces.emplace_back(vertexStartIndex + 15, vertexStartIndex + 16, vertexStartIndex + 17); mFaces.emplace_back(vertexStartIndex + 18, vertexStartIndex + 19, vertexStartIndex + 20); mFaces.emplace_back(vertexStartIndex + 21, vertexStartIndex + 22, vertexStartIndex + 23); } unsigned int numVertices = static_cast(mVertices.size() - vertexStartIndex); if (numVertices > 0) { // create a bone affecting all the newly created vertices aiBone *bone = new aiBone; mBones.push_back(bone); bone->mName = pNode->mName; // calculate the bone offset matrix by concatenating the inverse transformations of all parents bone->mOffsetMatrix = aiMatrix4x4(pNode->mTransformation).Inverse(); for (aiNode *parent = pNode->mParent; parent != nullptr; parent = parent->mParent) bone->mOffsetMatrix = aiMatrix4x4(parent->mTransformation).Inverse() * bone->mOffsetMatrix; // add all the vertices to the bone's influences bone->mNumWeights = numVertices; bone->mWeights = new aiVertexWeight[numVertices]; for (unsigned int a = 0; a < numVertices; ++a) { bone->mWeights[a] = aiVertexWeight(vertexStartIndex + a, 1.0); } // HACK: (thom) transform all vertices to the bone's local space. Should be done before adding // them to the array, but I'm tired now and I'm annoyed. aiMatrix4x4 boneToMeshTransform = aiMatrix4x4(bone->mOffsetMatrix).Inverse(); for (unsigned int a = vertexStartIndex; a < mVertices.size(); a++) mVertices[a] = boneToMeshTransform * mVertices[a]; } // and finally recurse into the children list for (unsigned int a = 0; a < pNode->mNumChildren; ++a) { CreateGeometry(pNode->mChildren[a]); } } // ------------------------------------------------------------------------------------------------ // Creates the mesh from the internally accumulated stuff and returns it. aiMesh *SkeletonMeshBuilder::CreateMesh() { aiMesh *mesh = new aiMesh(); // add points mesh->mNumVertices = static_cast(mVertices.size()); mesh->mVertices = new aiVector3D[mesh->mNumVertices]; std::copy(mVertices.begin(), mVertices.end(), mesh->mVertices); mesh->mNormals = new aiVector3D[mesh->mNumVertices]; // add faces mesh->mNumFaces = static_cast(mFaces.size()); mesh->mFaces = new aiFace[mesh->mNumFaces]; for (unsigned int a = 0; a < mesh->mNumFaces; a++) { const Face &inface = mFaces[a]; aiFace &outface = mesh->mFaces[a]; outface.mNumIndices = 3; outface.mIndices = new unsigned int[3]; outface.mIndices[0] = inface.mIndices[0]; outface.mIndices[1] = inface.mIndices[1]; outface.mIndices[2] = inface.mIndices[2]; // Compute per-face normals ... we don't want the bones to be smoothed ... they're built to visualize // the skeleton, so it's good if there's a visual difference to the rest of the geometry aiVector3D nor = ((mVertices[inface.mIndices[2]] - mVertices[inface.mIndices[0]]) ^ (mVertices[inface.mIndices[1]] - mVertices[inface.mIndices[0]])); if (nor.Length() < 1e-5) /* ensure that FindInvalidData won't remove us ...*/ nor = aiVector3D(1.0, 0.0, 0.0); for (unsigned int n = 0; n < 3; ++n) mesh->mNormals[inface.mIndices[n]] = nor; } // add the bones mesh->mNumBones = static_cast(mBones.size()); mesh->mBones = new aiBone *[mesh->mNumBones]; std::copy(mBones.begin(), mBones.end(), mesh->mBones); // default mesh->mMaterialIndex = 0; return mesh; } // ------------------------------------------------------------------------------------------------ // Creates a dummy material and returns it. aiMaterial *SkeletonMeshBuilder::CreateMaterial() { aiMaterial *matHelper = new aiMaterial; // Name aiString matName(std::string("SkeletonMaterial")); matHelper->AddProperty(&matName, AI_MATKEY_NAME); // Prevent backface culling const int no_cull = 1; matHelper->AddProperty(&no_cull, 1, AI_MATKEY_TWOSIDED); return matHelper; }